Infusion, curing, pickling, injection and marination of meat and food substances has been in practice for many years. The initial most common method was to submerge the material in a solution of marination, pickle solution, or brine for long periods of time. This could take one or more days depending upon the level of uptake of the solution. The industry progressed from that practice to either a needle injection or a massaging method using an upright drum, filled with product and the marination solution, with an agitator. The multi-vane agitator would travel in slow rotational speed in one direction for several minutes and then in the reverse direction. This process would take 20 to 30 hours for marination of meat.
That practice progressed to turning the drum on its side, loading the meat and marination solution, closing the doors and rotating the drum. Vanes were built into the walls of the drum to create more massaging action on the product. This method would later be enhanced by adding a vacuum pump to evacuate the air inside the drum, thus keeping down foaming and removing air from the product. This method would take 20 to 30 minutes to complete a marination cycle. These drums would hold on an average 3000 to 5000 pounds of product, with some as high as 20,000 pounds.
Typical process enhancements would be to pre-chill the product down to near freezing levels to stiffen the muscles, thus causing more massaging during tumbling. CO2 would also be injected into the tumbler during rotation or a refrigerated jacket around the outside of the tumbler would be used to further chill the product.
In these prior processes, the meat massaging action would result primarily from (a) the meat pieces themselves imparting forces one to another, (b) the vanes (if present) creating a force on the bulk of the meat mass, and (c) the meat falling into the drum wall and onto other pieces due to the rotation of the drum. None of these methods provide direct massaging of each individual piece of meat. Moreover, these meat marinators/massagers operate in a batch mode off-line from the main processing line. Marinated meat is staged into the constant flow of a processing line either by surge hoppers, conveyers, or push carts typically loaded with 300 to 500 pounds of meat.
The marination pick-up achieved in these prior processes has usually been limited to the exterior portions of the meat substance with only slight infusion into the body of the muscle. Because the meat pieces themselves are massaging one another, the tougher muscles receive much less massaging pick up and thus much less infusion of marination. The structure of this meat is very tight, allowing for minimum infusion of external liquid.
The vacuum tumbler and other conventional tumbling systems used heretofore have typically been “dry” marination systems wherein the amount of marination fluid placed in the tumbler equals or only minimally exceeds the amount of fluid which is actually infused into the product. For example, when processing poultry wings to obtain an eight percent pickup of marination solution, only eight pounds of marination fluid would be placed in the batch tumbling drum per each 100 pounds of wings. Thus, as the liquid becomes fully absorbed into the bulk product, the individual pieces thereof tumble onto and collide with each other.
Although the type of colliding interaction experienced in prior art tumblers can beneficially act to move protein from the interior of the product to the surface, it undesirably limits the amount of marinade pick up which can be achieved. The internal pressure created by the weight and momentum of the product pieces not only causes internal protein to flow to the surface but also causes the marinade solution to flow out of, rather than into, the product.
Additional disadvantages and shortcomings of the prior art batch tumbling systems are that (a) they typically require the installation, operation, and maintenance of vacuum pumps, (b) because the individual pieces of each product batch must be held in hoppers and fed to downstream processing units over a period of time, significant differences in drying, aging, moisture content, etc. can occur, thus resulting in a lack of product consistency and uniformity and lower quality, and (c) the colliding interaction of the product pieces not only causes marinade to flow out of the product but undesirably causes fat to flow out of the product as well.
Tenderization of meat muscle is usually performed by slashing or thin blade cutting the muscle, thus severing the connective collagen fibers. This reduces the toughness of the meat but also has a negative effect in that the overall structure is severely disturbed. A more natural tenderization method, much like the “hammering” of the meat commonly done in the home, is more desirable. However, this method damages the protein of the muscle.
Thus, a need presently exists for 1) an improved method of marinade infusion, 2) a continuous, real-time process which continuously delivers marinated meat directly into the processing line, and 3) a more effective, continuous method of tenderization which does not seriously either damage the muscle protein or disturb the overall structure of the product.